Why we must strive to protect our ink-black skies

MAJESTIC: Phillip O'Neill says gazing at a moonless Hunter Valley sky is a tremendous joy. "I’ve never met a person not enthralled by the wonder of it all."

I’ve just finished reading Walking with Plato. It is a diary of journalist Gary Hayden and his school teacher wife Wendy as they walk the length of Britain from John o’Groats in Scotland to Lands’ End at the tip of Cornwall.

The book is a delightful account of the history and geography of Britain, witnessed from trails that wind their way through that isle’s wilder parts. It is a tribute to British custody of its many wonderful landscapes through the centuries, especially their survival through the industrial transformations of the last 200 years.

But there is one landscape that our diarist admits faces extinction: the dark, clear night-sky. During their trek along a remote part of Hadrian’s Wall – the fortification across southern Scotland of the old Roman Empire – Gary Hayden finds himself staring into a moonless sky. Fascinated by the universe above, he lies outside his tent gazing at the stars into the early hours of the morning. Hayden writes of that feeling of being an insignificant dot on a little planet on the edge of one luminescent cloud of galaxies after another across an ink-black sky.

The episode reminded me of a column I wrote about the absence of stars in the night sky a few years back when we were living in London. I recounted a local saying you can see London from outer space, but you can’t see outer space from London.

When I drove back to our Hunter township from Sydney late last week there was night light from a fledgling moon, but still I was struck with the clarity of my view of the universe. The glow of Newcastle to the east seemed to stop at Sugarloaf and our local street lights didn’t dilute the darkness too much, although I do wonder why all that glare is necessary.

A recent scientific study reported in the journal Science Advances shows that we should be worried about the loss of the ink-black sky. Artificial light continues its colonisation of the night. And this involves more than not being able to stare into infinity. The stress of not having dark nights is affecting the vigour of life on our planet. Organisms, like us, that need darkness to sleep suffer when the natural day-night cycle loses its intensity. Then, those organisms that are nocturnal – apparently 30 per cent of the world’s vertebrates and more than 60 per cent of its invertebrates – suffer because the loss of darkness curtails what they can do during their waking hours.

Economic growth and urbanisation are the main causes of night time light pollution. An intriguing finding of the study is the effect of LED lights. These not only make outside lighting cheaper, hence more prolific, they emit white-toned light different to the softer yellowish light from the old sodium bulbs, which makes the atmosphere glow brighter.

The study shows Australia’s night skies are getting brighter, but not to the extent found overseas. In Gary Hayden’s Britain, half of its children are said to have never seen the Milky Way.

There are about 100 billion stars in the Milky Way. My calculation says this is about one star for each person who has ever lived. Beyond the Milky Way there are two trillion more galaxies.

Gazing skyward on a moonless Hunter Valley night is a great joy. Stars stretch forever. I’ve never met a person not enthralled by the wonder of it all.

Some say they feel a very small part of something marvellous. I say we need to play a bigger part to protect what we’ve got.

Phillip O’Neill is professor of economic geography at Western Sydney University.